Along with the aforementioned fish, there are also the multitudes of _Hyphalosaurus_ and _Keichousaurus_ fossils; many of which show these agonized poses.
Some examples:
http://www.piinc.biz/images/Vertebrate%20fossils/Hyphalosaurus1BL.JPG http://www.cretaceousfossils.com/images/dinosaurs_and_nondinosaurian_reptiles/hyphalosaurus_lingyuanensis_1.jpg http://www.redicecreations.com/specialreports/2006/04apr/dragontheories.jpg http://pharyngula.org/images/keichousaurus.jpg